Prepare the Sauce: In a small bowl, whisk together tomato paste, ketchup, water, and salt until smooth and spreadable.

Arrange the "Crust": Line a large baking sheet with parchment paper. Place toast bread slices in a single layer, fitted closely together.

Apply Sauce: Spread a thin, even layer of the prepared pizza sauce over each slice of bread, reaching the edges.

Cheese Layer: Sprinkle a generous layer of shredded mozzarella over the sauce to act as "glue" for the toppings.

Add Toppings: Distribute the sliced sausage, diced red and green peppers, corn, and black olives evenly across the slices.

Bake: Place in a preheated oven at 210°C (410°F) with both top and bottom heat enabled.

Cook to Golden: Bake for approximately 20 minutes, or until the cheese is bubbly and the edges of the bread are golden brown and crispy.

Serve: Remove from the oven and serve immediately while the cheese is hot and melty.